Abstract:
Methods and structures are disclosed demultiplexing optical signals transmitted over an optical fiber into a silicon substrate and to multiple detectors. The silicon substrate has two spaced-apart surfaces and a diffractive element disposed adjacent to one of the surfaces. Each of the optical signals corresponds to one of multiple wavelengths. The optical signals are directed into the silicon substrate along a path through the first surface to be incident on the diffractive element. The path is oriented generally normal with the first surface and/or with the diffractive element, which angularly separates the optical signals such that each of the wavelengths traverses through the substrate in a wavelength dependent direction to the first surface. Each optical signal is steered from the first surface towards the second surface to be incident on different optical elements that direct them generally normal to the first surface to be incident on one of the detectors.
Abstract:
A nuclear reactor system having a water-cooled reactor includes a reactor containment. A shielding pit inside the reactor containment has a lower region with an outlet opening formed therein. A reactor pressure vessel is disposed in the shielding pit. A moderating cell is disposed downstream of the outlet opening and has a device for slowing down and diverting a melt flowing through the outlet opening. A catch basin is disposed downstream of the moderating cell for receiving a melt and a supply of water. A method for operating a nuclear reactor system includes covering the bottom of the catch basin with water during normal operation of the reactor, and maintaining the water in the catch basin at a surface level being lower than the lowermost region of the bottom of the shielding pit.
Abstract:
Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.
Abstract:
Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.
Abstract:
Methods and structures are disclosed demultiplexing optical signals transmitted over an optical fiber into a silicon substrate and to multiple detectors. The silicon substrate has two spaced-apart surfaces and a diffractive element disposed adjacent to one of the surfaces. Each of the optical signals corresponds to one of multiple wavelengths. The optical signals are directed into the silicon substrate along a path through the first surface to be incident on the diffractive element. The path is oriented generally normal with the first surface and/or with the diffractive element, which angularly separates the optical signals such that each of the wavelengths traverses through the substrate in a wavelength dependent direction to the first surface. Each optical signal is steered from the first surface towards the second surface to be incident on different optical elements that direct them generally normal to the first surface to be incident on one of the detectors.
Abstract:
A method involving: providing an optical waveguide made of a semiconductor material and having a region that is doped by a deep level impurity which creates deep level states in a bandgap in the semiconductor material, the deep level states characterized by an occupancy; passing an optical signal through the optical waveguide and between the region doped by the deep level impurity; and modulating the occupancy of the deep level states to thereby modulate the optical signal.
Abstract:
FET configurations in which two (or more) facets are exposed on a surface of a semiconductor channel, the facets being angled with respect to the direction of the channel, allow for conformal deposition of a convex or concave S/D. A convex tip of the S/D enhances electric fields at the interface, reducing the resistance between the S/D and the channel. In contrast, a S/D having a concave tip yields a dual-gate FET that emphasizes reduced short-channel effects rather than electric field enhancement. The use of self-limiting, selective wet etches to expose the facets facilitates process control, control of interface chemistry, and manufacturability.
Abstract:
A method involving: providing an optical waveguide made of a semiconductor material and having a region that is doped by a deep level impurity which creates deep level states in a bandgap in the semiconductor material, the deep level states characterized by an occupancy; passing an optical signal through the optical waveguide and between the region doped by the deep level impurity; and modulating the occupancy of the deep level states to thereby modulate the optical signal.
Abstract:
A method of fabricating on a substrate an optical detector in an optical waveguide, the method involving: forming at least one layer on a surface of the substrate, said at least one layer comprising SiGe; implanting an impurity into the at least one layer over a first area to form a detector region for the optical detector; etching into the at least one layer in a first region and a second region to form a ridge between the first and second regions, said ridge defining the optical detector and the optical waveguide; filling the first and second regions with a dielectric material having a lower refractive index than SiGe; and after filling the first and second regions with the dielectric material, removing surface material to form a planarized upper surface.
Abstract:
Methods and structures are disclosed demultiplexing optical signals transmitted over an optical fiber into a silicon substrate and to multiple detectors. The silicon substrate has two spaced-apart surfaces and a diffractive element disposed adjacent to one of the surfaces. Each of the optical signals corresponds to one of multiple wavelengths. The optical signals are directed into the silicon substrate along a path through the first surface to be incident on the diffractive element. The path is oriented generally normal with the first surface and/or with the diffractive element, which angularly separates the optical signals such that each of the wavelengths traverses through the substrate in a wavelength dependent direction to the first surface. Each optical signal is steered from the first surface towards the second surface to be incident on different optical elements that direct them generally normal to the first surface to be incident on one of the detectors.